[avdept]

Hey folks, I have weird issue when car wont start for something like first 10-15 minutes in the morning. It turns on(music, AC, etc) but not engines and throws drive malfunction error. However after about 10-15 minutes and few restarts car starts up as nothing happened and drives with no errors, charges, goes to sport mode, etc. and it works till car stays overnight. I replaced 12v battery with brand new BMW, but that didn't help.

I've attached link to ISTA readings of error codes(the one with FLER module was resolved as it was missing turning signal module)

Just a bit of context - car was in accident and I restored it. During restoration I was driving it(testing) and it never had this issue. I had it first time when I installed headlights(brand new with used ballast modules) and flashed to car 4 new modules - LIM, DSC, 2 headlights.

I checked HV battery stats, voltages(via ISTA) to see if there might be any faulty module but it all are good(which confirms when I drive it hardly in sport mode or fully electric).

For now, the only other issue I have - sometimes front PDC stops work and complains on short circuit to ground. I tested and it doesn't really have short circuit since the wire loom in bumper brand new and the opposite loom + connector all good and undamaged. I suspect it might be one of PDC sensors, since when it works one of them is completely blind unless you move hand to like 1-2cm from it.

I also put it on charger every evening, so in morning its full(charges, flashes green when I remove charging plug) but then when I try to start it it wont even charge too

So any ideas what can be wrong based on my text and attached error codes?


Error codes:
https://monosnap.com/file/iX76NjvUe8...et3seTosOYMyCZ

[zorgzx]

You have a lot of high voltage errors, perhaps its angry that the command to start high voltage fails. then after a while the high voltage starts ? Theres a Thermal fault, is your battery conditioning working ?

I would try to heve the AC run pre drive, to see if that clears the problem.

Just random thoughts.

[avdept]

Originally Posted by zorgzx

You have a lot of high voltage errors, perhaps its angry that the command to start high voltage fails. then after a while the high voltage starts ? Theres a Thermal fault, is your battery conditioning working ?

I would try to heve the AC run pre drive, to see if that clears the problem.

Just random thoughts.

IS AC runs off high voltage or off 12v?

Conditioning working well, and when in morning, its about 15C, so I don't think there's heating issue, rather more like some on NTC(temperature) sensors on battery reports some faulty value, but there isn't error about that.

[zorgzx]

from what i can see my car uses the high voltage battery for AC, then starts charging the High voltage when plugged in. Ofcourses needs 12v to power the electronics like all EV's, achilles.

Was just wondering if having it conditioned would make a difference. Guess you have one of the many fault values that are not read out diractly to the ECU. I'm officially out of my leauge.

[avdept]

Did experiment today, didn't put it on charger, in case charger is bad or something else related. But that didn't really help either. Im really considering remove the battery and replace modules with higher capacity as other guy recently did and also check if there's any issues with NTCs

[zorgzx]

Just occurred to me you have a 8yr 100kmls warranty on the battery so why not just dump it with bmw, and at the same time have them run the milage test. If you have intermittent fault, my guess is range is below the req.

[avdept]

I tracked it down to one of CSC(bms) and incorrect temperature reading. I will do CSC tests via ISTA, but seems like I'll have to remove battery and either replace CSC or faulty temp sensor


Im also considering following Flasher path to upgrade 20Ah to 34AH packs

[avdept]

Originally Posted by zorgzx

Just occurred to me you have a 8yr 100kmls warranty on the battery so why not just dump it with bmw, and at the same time have them run the milage test. If you have intermittent fault, my guess is range is below the req.

I can't do it because it was exported from US and imported to EU, and car was after accident, so I think warranty not applies anymore

[avdept]

Ok, I did a bit more digging, found faulty NC sensor. I monitored in live mode and it eventually moves from -2C to proper ~25C to match other sensors. Also i8 will not switch contactors(or disconnect them) in case when temp difference between low and high values more than 5C degree. I didn't find what NTCs they used, so I took a risk, ordered few different to see which ones matches close to other sensors. Also ordered battery seal(big and small), not sure if they need to be replaced when you open battery, so if anyone has information on that - would help a lot.

[avdept]

Fixed. Replaced faulty sensor inside HV cell. Now all works like it should.

[stressdoc]

Impressive troubleshooting!

[avdept]

Originally Posted by stressdoc

Impressive troubleshooting!

Thanks. I posted more detailed update in FB group - https://www.facebook.com/groups/bmwi...8930419688117/

Can't post here since I can't upload photos directly.

Sorry if Im not allowed to share FB links